net: stmmac: refactor FPE verification process

Drop driver defined stmmac_fpe_state, and switch to common
ethtool_mm_verify_status for local TX verification status.

Local side and remote side verification processes are completely
independent. There is no reason at all to keep a local state and
a remote state.

Add a spinlock to avoid races among ISR, timer, link update
and register configuration.

This patch is based on Vladimir Oltean's proposal.

Vladimir Oltean says:

  ====================
  In the INITIAL state, the timer sends MPACKET_VERIFY. Eventually the
  stmmac_fpe_event_status() IRQ fires and advances the state to VERIFYING,
  then rearms the timer after verify_time ms. If a subsequent IRQ comes in
  and modifies the state to SUCCEEDED after getting MPACKET_RESPONSE, the
  timer sees this. It must enable the EFPE bit now. Otherwise, it
  decrements the verify_limit counter and tries again. Eventually it
  moves the status to FAILED, from which the IRQ cannot move it anywhere
  else, except for another stmmac_fpe_apply() call.
  ====================

Co-developed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Furong Xu <0x1207@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/151f86c8428eba967039718c6bf90a7d841e703b.1725631883.git.0x1207@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 16 insertions, 20 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 3ad182ef8e97..ea135203ff2e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -146,31 +146,30 @@ struct stmmac_channel {
 	u32 index;
 };
 
-/* FPE link state */
-enum stmmac_fpe_state {
-	FPE_STATE_OFF = 0,
-	FPE_STATE_CAPABLE = 1,
-	FPE_STATE_ENTERING_ON = 2,
-	FPE_STATE_ON = 3,
-};
-
 /* FPE link-partner hand-shaking mPacket type */
 enum stmmac_mpacket_type {
 	MPACKET_VERIFY = 0,
 	MPACKET_RESPONSE = 1,
 };
 
-enum stmmac_fpe_task_state_t {
-	__FPE_REMOVING,
-	__FPE_TASK_SCHED,
-};
+#define STMMAC_FPE_MM_MAX_VERIFY_RETRIES	3
+#define STMMAC_FPE_MM_MAX_VERIFY_TIME_MS	128
 
 struct stmmac_fpe_cfg {
-	bool enable;				/* FPE enable */
-	bool hs_enable;				/* FPE handshake enable */
-	enum stmmac_fpe_state lp_fpe_state;	/* Link Partner FPE state */
-	enum stmmac_fpe_state lo_fpe_state;	/* Local station FPE state */
+	/* Serialize access to MAC Merge state between ethtool requests
+	 * and link state updates.
+	 */
+	spinlock_t lock;
+
 	u32 fpe_csr;				/* MAC_FPE_CTRL_STS reg cache */
+
+	enum ethtool_mm_verify_status status;
+	struct timer_list verify_timer;
+	bool verify_enabled;
+	int verify_retries;
+	bool pmac_enabled;
+	u32 verify_time;
+	bool tx_enabled;
 };
 
 struct stmmac_tc_entry {
@@ -367,10 +366,6 @@ struct stmmac_priv {
 	struct work_struct service_task;
 
 	/* Frame Preemption feature (FPE) */
-	unsigned long fpe_task_state;
-	struct workqueue_struct *fpe_wq;
-	struct work_struct fpe_task;
-	char wq_name[IFNAMSIZ + 4];
 	struct stmmac_fpe_cfg fpe_cfg;
 
 	/* TC Handling */
@@ -425,6 +420,7 @@ bool stmmac_eee_init(struct stmmac_priv *priv);
 int stmmac_reinit_queues(struct net_device *dev, u32 rx_cnt, u32 tx_cnt);
 int stmmac_reinit_ringparam(struct net_device *dev, u32 rx_size, u32 tx_size);
 int stmmac_bus_clks_config(struct stmmac_priv *priv, bool enabled);
+void stmmac_fpe_apply(struct stmmac_priv *priv);
 
 static inline bool stmmac_xdp_is_enabled(struct stmmac_priv *priv)
 {